LSD Flashbacks: Are They Real?

Learn about LSD flashbacks and Hallucinogen Persisting Perception Disorder in this comprehensive exploration.

Overview: Hallucinogen Persisting Perception Disorder (HPPD) is a complex condition resulting from the use of psychedelic substances, characterized by persistent perceptual disturbances. It is categorized into HPPD I, which is short-term and reversible, and HPPD II, which is long-term and irreversible. The varied symptoms associated with HPPD extend beyond the classifications of the DSM-5 and encompass visual hallucinations, altered motion perception, flashes of color, and more. The elusive causes of HPPD are theorized to involve disruptions in the brain and various environmental triggers. Treatment options for HPPD are diverse, emphasizing personalized care tailored to individual needs. The prevalence of HPPD is challenging to pinpoint, complicating research efforts. Ongoing studies are dedicated to unraveling the complexities of HPPD, underscoring the importance of understanding and promoting safe psychedelic usage.

Beyond the Trip: LSD's Lasting Effects and the Mystery of HPPD

Synthesized by Swiss chemist Albert Hofmann in 1938, LSD is known for its profound effects on perception, cognition, and emotions, leading to altered states of consciousness commonly referred to as “trips.”

The effects of LSD can vary from person to person, but broadly speaking, they are often classified into cognitive, emotional, perceptual, and ego-related categories. Explore the profound and varied effects of LSD by delving into our comprehensive blog on the subject, offering insights and information for a deeper understanding: Effects of LSD

While LSD can lead to profound and diverse experiences, it's important to acknowledge a phenomenon known as Hallucinogen Persisting Perception Disorder (HPPD). HPPD involves the recurrence of perceptual disturbances, akin to those experienced during a psychedelic trip, persisting beyond the drug’s immediate effects.

This condition can manifest as ongoing visual disturbances, such as visual snow, halos around objects, or trails behind moving objects, even in the absence of LSD consumption. Understanding the range of effects and potential long-term repercussions of psychedelic substances like LSD is crucial for promoting informed and safe usage.

What is Hallucinogen Persisting Perception Disorder?

HPPD is a unique condition characterized by the reappearance of perceptual effects previously encountered during the use of psychedelic drugs. This recurrence involves either the complete or partial return of perceptual phenomena without recent drug intake, setting it apart from common “flashbacks” associated with drug use.

Colloquially referred to as “LSD flashbacks,” HPPD is distinguished in the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5) — a manual that provides criteria for the classification and diagnosis of mental disorders — by its association with significant distress or functional impairment.

While flashbacks are a known phenomenon, HPPD stands out due to the intensity of perceptual effects and the impact on daily life. HPPD involves more persistent and profound perceptual effects beyond what is typically associated with the term “flashbacks.”

A latent period often precedes the onset of recurring visual occurrences associated with HPPD. These visual phenomena, lasting from minutes to hours, or even persisting for days to years, can re-emerge with or without any recognized or perceived precipitator.

The prevalence of HPPD remains elusive, adding to its enigmatic nature. Initial estimates suggested its occurrence in approximately 1 in 50,000 psychedelic users. However, recent findings from a web-based survey indicate that 4.2% of 2,455 respondents reported persistent visual phenomena accompanied by clinically significant distress, aligning with HPPD criteria. Pinpointing the exact prevalence is challenging due to limited large-scale studies and population data.

HPPD is not limited to individuals with a history of psychological issues or substance misuse; it can occur after a single exposure to certain substances, even if they are not necessarily psychedelics. The overlap of HPPD with drug-induced psychosis and other conditions makes it challenging for researchers to understand the occurrence, pattern, and contributing factors of this disorder within specific populations.

In recent years, efforts to classify persisting perceptual disorders have evolved. A proposed review suggests categorizing these disturbances into two syndromes: HPPD 1, denoting transient and benign re-experiencing of perceptual symptoms, and HPPD 2, also known as HPPD Type II, characterizing chronic and distressing visual disturbances. However, these criteria have not yet been accepted by DSM-5.

Despite ongoing research, HPPD remains a poorly understood aspect of psychedelic drug use. The complex interplay of individual factors, limited prevalence data, and the nuanced classification of persisting perceptual disorders contribute to the ongoing challenge of comprehending and addressing this unique condition.

Distinguishing Between HPPD Type I and HPPD Type II

The DSM-5 currently lacks a specific differentiation between HPPD I and HPPD II, and ongoing debates surround their distinctions.

The International Classification of Disease, 10th edition (ICD-10), a global standard for reporting various health conditions, aligns more closely with HPPD I, while HPPD II better corresponds to the criteria outlined in the DSM-5, which specifically focuses on mental disorders.

Episodes of both HPPD I and II may surface spontaneously or be triggered by identifiable and unidentified factors. Importantly, these episodes can take various forms, appearing as continuous, intermittent, or sudden occurrences. The distinction between HPPD I and HPPD II is better framed by their expected outcomes rather than immediate symptoms

HPPD Type I: Short-Term, Reversible, and Benign

HPPD Type I typically follows a less severe and reversible path. People with this type might experience brief and recurring perceptual effects that remind them of their initial psychedelic experience.

While visual images may provoke mild discomfort, re-experiencing them typically does not lead to significant concern, distress, or impairment in various areas of life such as individual, familial, social, or occupational functioning. These experiences are also typically less frequent in HPPD I compared to HPPD II. 

The impairment is generally mild, and the prognosis is typically favorable. Some patients even view these perceptual experiences as “free trips,” resembling psychedelic experiences without the need for consuming a psychedelic substance. 

The onset of HPPD I often comes with warning ‘auras,’ characterized by minor feelings of self-detachment, mild bewilderment, and mild depersonalization and derealization. ‘Auras’ in this context refer to premonitory sensations or warning signs, while depersonalization and derealization involve feelings of detachment from oneself and the external world.

HPPD Type II: Long-Term, Irreversible or Slowly Reversible, and Pervasive

In contrast, HPPD II follows a more persistent and severe course. The effects are long-lasting, with the impairment being severe and often irreversible or slowly reversible. Individuals with HPPD II may find it challenging to adapt to these recurrent effects, and a notable percentage may require ongoing treatment.

This type of HPPD may co-occur with other mental health conditions such as Major Depressive Disorder, Bipolar Disorder, and Schizophrenia Spectrum Disorders. The onset of HPPD II is often associated with negative mood and affect, and anxiety and depressive features can exacerbate new episodes. The prognosis for HPPD II is generally less optimistic, and some individuals may struggle to live with the persistent effects, necessitating ongoing care.

Importantly, while HPPD II may be linked to other mental health disorders, both HPPD I and HPPD II can manifest independently, and their onsets are not necessarily accompanied by other mental health conditions.

The onset of HPPD II may come on abruptly and unexpectedly, characterized by strong auras, deep feelings of self-detachment, and more severe depersonalization and derealization. After HPPD II onset, psychedelic events tend to occur more frequently than HPPD I, and their duration and intensity increase. Individuals might perceive a partial or total loss of control

Understanding these distinctions is crucial for accurate diagnosis, appropriate treatment, and addressing the unique challenges posed by each type of HPPD.

An AI-generated image representing flashbacks, a common symptom of HPPD (Hallucinogen Persisting Perception Disorder).

Symptoms of HPPD

The spectrum of perceptual effects and visual imagery is diverse and vast, yet only a limited number of symptoms have found their way into the scientific literature. While the DSM-5 primarily outlines visual disturbances as the main group of symptoms, every perceptual effect encountered during a psychedelic experience has the potential to resurface in HPPD. 

Researchers have compiled a comprehensive list of common symptoms associated with HPPD. This list includes a range of perceptual disturbances and experiences that individuals with HPPD may undergo: 

  • Visual hallucinations : Perceptions in the absence of the objects. False perceived objects are often geometric figures.
  • Altered motion perception: False perceptions of movement in the peripheral visual fields.
  • Flashes of color
  • Color enhancement: Perception of intensified colors.
  • Trails or tracers: Lines, stripes or bands that could be observed after animate and inanimate objects have already moved from their previous location e.g. images left suspended in the path of a moving object as seen in stroboscopic photography. 
  • Palinopsia: Positive afterimages that continue to appear in one’s vision after the exposure to the original image has ceased.
  • Halos: Colored light around a light source or an object.
  • Micropsia: Misperception of images as too small.
  • Macropsia: Misperception of images as too large.

Common Symptoms Not Reported by DSM-5

  • Floaters: Spots that seem to drift in front of the eye.
  • Visualizations : Dots, points, particles, mottles or specks emerging in an obscure room.
  • Fractals: Self-similarity perception or small parts that are seen having an equal and identical shape or form as the whole.
  • Repetitions: Recurrence of inanimate or moving patterns or motives.
  • Keenness: Undimmed color contrasts.
  • Pareidolia: Perceiving a pattern, image, or meaningful object, such as faces or recognizable shapes, in a foggy arrangement (e.g. clouds, stains, or patterns). 
  • Superimpositions: Superimposed or overlapped geometric patterns.
  • Distorted Perception of Distance: Objects were seen slightly closer or distant.
  • Monochromatic Vision: The visual perception of distinct colors as one unique color with different tinges and tonalities.
  • Intense fragmentation: The sense of disintegration of still or moving objects.
  • Recurrent Synesthesia: Stimulation of one sensory pathway leads to automatic, involuntary reactions or experiences in a second sensory pathway.
  • Geometric Phosphenes: Seeing light without light penetrating the eye.
  • Imagistic Phosphenes: Casual and unplanned formed images like non-humans (zoopsia) and human faces without geometric patterns or figures provoked by closing an eye and pressing it with a finger.
  • Acquired Dyslexia: Difficulty with reading notwithstanding normal intelligence.
  • Aeropsia or Visual Snow: Virtually seeing particles of air.

Exploring Possible Causes of HPPD

Understanding why HPPD happens is made quite complex due to the variability of the recurring sensory issues it brings and the different subtypes involved. While the exact cause remains poorly understood, researchers have ventured into understanding the potential mechanisms at play within the brain.

One theory suggests that LSD use might disturb normal brain functions, creating an ongoing visual glitch. This disruption may arise from LSD-induced intense energy flows damaging or altering specific brain regions responsible for sensory control. The effectiveness of certain treatments for HPPD supports this concept. Additionally, even after discontinuing LSD use, the brain may continue reacting in ways that bring back unusual experiences. Interestingly, similar occurrences have been reported by individuals who have never used LSD.

Zooming into the brain’s larger structures, one avenue of exploration centers on temporary or permanent impairment of the Lateral Geniculate Nucleus (LGN). The LGN is a structure within the thalamus, which is deeper in the brain. It processes visual information received from the eyes before transmitting it to the visual cortex and is a key relay station in the visual pathway. 

Hypotheses have also been posited regarding the right lingual gyrus. The right lingual gyrus is a part of the occipital lobe, located at the back of the brain. It is primarily involved in visual processing and plays a role in tasks related to visual recognition, perception, and memory.

Another line of thought proposes that HPPD may be linked to heightened activity in specific brain pathways, particularly those governing visual processing. This intensified activity could exacerbate anxiety, especially following the use of drugs affecting alertness, even if non-psychedelic. This concept challenges the direct association between psychedelics and HPPD, suggesting that existing mental health conditions may play a more significant role.

Additionally, some experts think that things in our surroundings or specific situations could act as triggers, bringing back memories of the original psychedelic experience and triggering HPPD-like moments. These are just some theories, and the mystery behind HPPD highlights the need for ongoing research to figure out its complicated causes.

Substances Linked to HPPD

The association between substances and HPPD encompasses a diverse range beyond traditional psychedelics. While LSD remains the most extensively studied substance linked to HPPD, the disorder has expanded its reach to include various classes of psychoactive compounds.

Here's a breakdown of substances implicated in the development of HPPD:

  • Cannabinoids:some text

  • Deliriantssome text
    • Datura stramonium (contains the psychoactive compounds scopolamine, atropine, and hyoscyamine) 

Notably, the majority of documented HPPD cases are associated with LSD or PCP.

A unique case has been reported where the atypical antipsychotic Risperidone induced HPPD. This suggests that HPPD is not exclusively linked to psychedelic consumption; rather, various substances across different categories may correlate with its onset.

Treatment Options for HPPD 

Finding  relief for Hallucinogen Persisting Perception Disorder (HPPD) involves considering various treatment options: 

  • Presynaptic α2 adrenergic agonists like Clonidine, Lofexidine, and Benzodiazepines are front-line choices, showing efficacy in alleviating symptoms. Clonazepam, a benzodiazepine, stands out for improving visual disturbances. These drugs work by activating specific receptors in the brain, influencing the release of neurotransmitters that can have a calming effect on the nervous system.
  • Antipsychotics, particularly Haloperidol and first-generation options, may be beneficial, while the use of second-generation antipsychotics is debated. Low doses of atypical antipsychotics like Aripiprazole might prove useful.
  • Antiepileptic drugs, such as Valproic Acid and Lamotrigine, can be considered, especially when mood disorders accompany visual disturbances.
  • Antidepressants like Sertraline and Norepinephrine reuptake inhibitors (NRIs) could be explored for co-occurring anxiety and depressive disorders associated with HPPD II.

Second-Line Medications and Brain Stimulation Treatments for HPPD

In cases where first-line treatments are insufficient, second-line medications and other treatment options have been explored for HPPD.

Naltrexone, an opioid antagonist, is considered for chronic patients with persistent visual imagery unresponsive to prior medications. Naltrexone has been explored for its potential effectiveness in alleviating symptoms associated with HPPD, although its use for this specific purpose may vary and should be carefully evaluated based on individual cases.

Calcium Channel Blockers and Beta Blockers, such as Propranolol and Atenolol, may help manage anxiety accompanying HPPD II. These medications work by modulating the activity of certain receptors in the nervous system, helping to alleviate symptoms such as anxiety.

Interestingly, brain stimulation treatments like Repetitive Transcranial Magnetic Stimulation (rTMS) show promise in modulating specific brain circuits. rTMS is a neurostimulation method that uses electromagnetic coils to deliver repetitive magnetic pulses to specific areas of the brain, influencing neural activity for therapeutic purposes. While there's no current study on rTMS for HPPD, its potential effectiveness is hypothesized based on the cortical hyperexcitability hypothesis which suggests that certain HPPD may be characterized by abnormal neural excitability in specific brain regions. Excitability is a fundamental property of neurons (nerve cells) that allows them to transmit and process information within the nervous system.

The treatment approach for HPPD varies depending on individual cases, and a careful evaluation of potential side effects is crucial for providing personalized care. Each person may respond differently to treatments, and considerations such as medical history, co-occurring conditions, and individual sensitivities play a significant role in determining the most suitable therapeutic interventions.

Personalized care ensures that the chosen treatments align with the specific needs and circumstances of each individual, optimizing the chances of effectiveness while minimizing potential risks and side effects.

Key Takeaways: What You Need to Know About HPPD

In conclusion, the exploration of HPPD sheds light on the complex nature of this condition. Stemming from the use of mind-altering substances, particularly LSD, HPPD involves the recurrence of perceptual disturbances that persist beyond the immediate effects of the drug. While categorized into two types, HPPD I and HPPD II, each with distinct characteristics and prognoses, the disorder remains poorly understood.

The onset of HPPD, whether short-term and reversible (HPPD I) or long-term and irreversible (HPPD II), poses unique challenges for accurate diagnosis and appropriate treatment. Symptoms encompass a diverse range of perceptual disturbances, extending beyond those outlined in the DSM-5. Floaters, visualizations, and distortions in distance perception are among the varied experiences reported by individuals with HPPD.

The elusive prevalence of HPPD, coupled with the overlapping factors with other mental health conditions, complicates the understanding of its occurrence. Ongoing research delves into potential causes, including disruptions in brain functions, the involvement of specific brain regions, and the influence of substances beyond traditional psychedelics.

Treatment options, ranging from presynaptic α2 adrenergic agonists to innovative brain stimulation techniques, underscore the importance of personalized care. Despite progress, HPPD remains a challenge, emphasizing the need for continued research to enhance our understanding and improve diagnostic accuracy and therapeutic interventions.

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